Assigning value Conditional statement Loops Examples
Computer Algebra SystemsFundamentals of Programming
Sándor [email protected]
http://compalg.inf.elte.hu/~czirbusz/
Department of Computer AlgebraInformatics Institute, ELTE
D2.711A
2011-2012 spring
http://compalg.inf.elte.hu/~czirbusz/
Assigning value Conditional statement Loops Examples
Index
1 Assigning valueIn MapleIn Sage
2 Conditional statementThe IF in MapleThe IF in Sage
3 LoopsIn Maple
The for/from loopThe for/in loopThe while loop
General loopsLoops in Sage
4 Examples
Assigning value Conditional statement Loops Examples
In Maple
In Maple
name := expr;(name1, ..., namen) := (expr1, ..., exprn);
Test it: assigned(name)Undoing it:
name:=’name’unassign(’name1’,’name2’,...)evaln( name );
The statement assign:assign(a,b), assign(A=B), assign(L) :
it evaluates both sides.
parameters in form “a,b”: a = b (for simple variables)parameters in form “A,B”: A,B expression sequences withsame length
Assigning value Conditional statement Loops Examples
In Maple
In Maple
name := expr;(name1, ..., namen) := (expr1, ..., exprn);Test it: assigned(name)
Undoing it:
name:=’name’unassign(’name1’,’name2’,...)evaln( name );
The statement assign:assign(a,b), assign(A=B), assign(L) :
it evaluates both sides.
parameters in form “a,b”: a = b (for simple variables)parameters in form “A,B”: A,B expression sequences withsame length
Assigning value Conditional statement Loops Examples
In Maple
In Maple
name := expr;(name1, ..., namen) := (expr1, ..., exprn);Test it: assigned(name)Undoing it:
name:=’name’unassign(’name1’,’name2’,...)evaln( name );
The statement assign:assign(a,b), assign(A=B), assign(L) :
it evaluates both sides.
parameters in form “a,b”: a = b (for simple variables)parameters in form “A,B”: A,B expression sequences withsame length
Assigning value Conditional statement Loops Examples
In Maple
In Maple
name := expr;(name1, ..., namen) := (expr1, ..., exprn);Test it: assigned(name)Undoing it:
name:=’name’
unassign(’name1’,’name2’,...)evaln( name );
The statement assign:assign(a,b), assign(A=B), assign(L) :
it evaluates both sides.
parameters in form “a,b”: a = b (for simple variables)parameters in form “A,B”: A,B expression sequences withsame length
Assigning value Conditional statement Loops Examples
In Maple
In Maple
name := expr;(name1, ..., namen) := (expr1, ..., exprn);Test it: assigned(name)Undoing it:
name:=’name’unassign(’name1’,’name2’,...)
evaln( name );
The statement assign:assign(a,b), assign(A=B), assign(L) :
it evaluates both sides.
parameters in form “a,b”: a = b (for simple variables)parameters in form “A,B”: A,B expression sequences withsame length
Assigning value Conditional statement Loops Examples
In Maple
In Maple
name := expr;(name1, ..., namen) := (expr1, ..., exprn);Test it: assigned(name)Undoing it:
name:=’name’unassign(’name1’,’name2’,...)evaln( name );
The statement assign:assign(a,b), assign(A=B), assign(L) :
it evaluates both sides.
parameters in form “a,b”: a = b (for simple variables)parameters in form “A,B”: A,B expression sequences withsame length
Assigning value Conditional statement Loops Examples
In Maple
In Maple
name := expr;(name1, ..., namen) := (expr1, ..., exprn);Test it: assigned(name)Undoing it:
name:=’name’unassign(’name1’,’name2’,...)evaln( name );
The statement assign:assign(a,b), assign(A=B), assign(L) :
it evaluates both sides.
parameters in form “a,b”: a = b (for simple variables)parameters in form “A,B”: A,B expression sequences withsame length
Assigning value Conditional statement Loops Examples
In Maple
In Maple
name := expr;(name1, ..., namen) := (expr1, ..., exprn);Test it: assigned(name)Undoing it:
name:=’name’unassign(’name1’,’name2’,...)evaln( name );
The statement assign:assign(a,b), assign(A=B), assign(L) :
it evaluates both sides.parameters in form “a,b”: a = b (for simple variables)
parameters in form “A,B”: A,B expression sequences withsame length
Assigning value Conditional statement Loops Examples
In Maple
In Maple
name := expr;(name1, ..., namen) := (expr1, ..., exprn);Test it: assigned(name)Undoing it:
name:=’name’unassign(’name1’,’name2’,...)evaln( name );
The statement assign:assign(a,b), assign(A=B), assign(L) :
it evaluates both sides.parameters in form “a,b”: a = b (for simple variables)parameters in form “A,B”: A,B expression sequences withsame length
Assigning value Conditional statement Loops Examples
In Sage
in Sage
Exept the variable “x” the [varlist =] var(’[varlist]’)declaration is compulsory. If the variables exist, then themvalue is deleted.
Assigning value: var = expressIn the same manner: var1, var2, . . . = kif1, kif2 ,. . . .If there is one variable and on the right side there areseveral expression, then the type of variables “tuple”.
Assigning value Conditional statement Loops Examples
In Sage
in Sage
Exept the variable “x” the [varlist =] var(’[varlist]’)declaration is compulsory. If the variables exist, then themvalue is deleted.Assigning value: var = express
In the same manner: var1, var2, . . . = kif1, kif2 ,. . . .If there is one variable and on the right side there areseveral expression, then the type of variables “tuple”.
Assigning value Conditional statement Loops Examples
In Sage
in Sage
Exept the variable “x” the [varlist =] var(’[varlist]’)declaration is compulsory. If the variables exist, then themvalue is deleted.Assigning value: var = expressIn the same manner: var1, var2, . . . = kif1, kif2 ,. . . .
If there is one variable and on the right side there areseveral expression, then the type of variables “tuple”.
Assigning value Conditional statement Loops Examples
In Sage
in Sage
Exept the variable “x” the [varlist =] var(’[varlist]’)declaration is compulsory. If the variables exist, then themvalue is deleted.Assigning value: var = expressIn the same manner: var1, var2, . . . = kif1, kif2 ,. . . .If there is one variable and on the right side there areseveral expression, then the type of variables “tuple”.
Assigning value Conditional statement Loops Examples
The IF in Maple
Conditional statement I
if cond1 thenstatement_sequ1
elif cond2 thenstatement_sequ2
elif cond3 thenstatement_sequ3............
elsestatement_sequN
end if
Assigning value Conditional statement Loops Examples
The IF in Maple
Conditional statement II
Constructing and evaluating conditional statements:
Relations: ,
Logical operators: and, or, xor, implies, not
Logical constants: true, false, FAIL
Boolean evaluation: evalb, testeq, or is
Remark: The logic in Maple interpreter is a trivalent logic.
Assigning value Conditional statement Loops Examples
The IF in Sage
Conditional statement
if cond1:statement_sequ1
elif cond2:statement_sequ2
elif cond3:statement_sequ3............
else:statement_sequN
There are not end of block statement; teh colon is compulsory.
Assigning value Conditional statement Loops Examples
The IF in Sage
Constructing conditional statements
Testing : expr1 == expr2 or kif1 is kif2
Logical operators: and, or, notThe logical evaluation is more natural the in maple.
Assigning value Conditional statement Loops Examples
The IF in Sage
Constructing conditional statements
Testing : expr1 == expr2 or kif1 is kif2Logical operators: and, or, not
The logical evaluation is more natural the in maple.
Assigning value Conditional statement Loops Examples
The IF in Sage
Constructing conditional statements
Testing : expr1 == expr2 or kif1 is kif2Logical operators: and, or, notThe logical evaluation is more natural the in maple.
Assigning value Conditional statement Loops Examples
In Maple
The for/from loop
for counter from init by increment to final dostatement_seq
end do
The clauses from, by and to are optional, they are in arbitraryorder. Default values: by =1, from = 0.
Assigning value Conditional statement Loops Examples
In Maple
The for/in loop
for variable in expr dostatement_seq
end do
The value of variable runs through all value of the compoundstructure "expr" and executed every time. Such is in PHP theloop foreach.
Assigning value Conditional statement Loops Examples
In Maple
The while loop
while condition dostatement_seq
end do
Assigning value Conditional statement Loops Examples
General loops
General loops
for counter from initial by increment to finalwhile condition dostatement_seqend do
for variable in expression while condition dostatement_seq
end do
Influencing the run of loop: break,next
Assigning value Conditional statement Loops Examples
Loops in Sage
The FOR iteration I
for counter in range():statement_seq
The parameters of range are the usual start value(the default is0), end value and the step (default = 1).Differently from other languages the loop does not run on theend value.Variants:
range : it makes a listxrange : it is an iterator, not a list, therefore it is faster.srange : it is the slower (there are other parameters), it
makes a list too.
Assigning value Conditional statement Loops Examples
Loops in Sage
The FOR iteration I
for counter in obj:statement_seq
here the “obj” is a compound object, mostly a list. The colon iscompulsory here; the body of loop continues until the end ofindentation.
Assigning value Conditional statement Loops Examples
Loops in Sage
The while loop
wile logical_cond:statement_seq
It is the usual while of Python.
Assigning value Conditional statement Loops Examples
Examples
In practice.
Assigning valueIn MapleIn Sage
Conditional statementThe IF in MapleThe IF in Sage
LoopsIn MapleGeneral loopsLoops in Sage
Examples
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